The next time you’re overcome by the temptations of an overflowing buffet table, you can attribute at least part of your overindulgence to natural instinct. Whether faced with an assortment of appetizers at a New Year’s Eve party or a bowl of candy on the counter, research shows being offered more variety compels us to eat more.

In fact, when provided with a large selection of foods, studies show people consume roughly 25% to 200% more food than if offered less variety. Additional research shows larger serving bowls lead us to take bigger portions, so it’s easy to see why the buffet trough can be so overpowering.

The first battle with the buffet is a mental one. It’s natural to equate eating more with “getting more for your money” in an all-you-can-eat restaurant. In reality, you pay the same amount whether you eat what you need or decide to overeat, so you’re not actually saving any money. We face similar pressure to eat at social gatherings, where frugality is not a concern. Many of us nosh absentmindedly out of a misplaced sense of politeness.

Buffets make portion control a challenge, as well. Even if you decide to merely “taste” everything, this nibbling leads most of us to consume much more food than we’d normally eat at a typical meal. And while the rules of excess also apply to selecting vegetables, many buffet lines offer a poor selection of produce or prepare it with excess fat and calories.